1. Field of the Invention
The present invention relates to a pointing device to direct movement of a target object.
2. Description of the Related Art
A technique to direct movement of an object is used in various apparatus such as a remote control device adapted to remotely control movement of a moving object, an input device such as a pointing device used in an information processing apparatus to direct movement of an object such as a pointer displayed on a display screen, etc. An input device to direct movement on a display screen is used in a wide variety of apparatus such as personal computers, portable telephone devices, PDA devices, portable game machines, etc. Such an input device allows a user to direct movement of an object of an image such as a cursor or a pointer displayed on a display screen, for example, to move the object in a drag-and-drop manner. In input devices for this purpose, it is desirable that they have a small size and besides they be flexibly and freely operable.
Many types of input devices for the above purpose are known. However, it is not easy to satisfy both requirements for small size and flexible operability. In general, a mouse is excellent in operability but it is difficult to realize a small-sized mouse. On the other hand, input devices such as joysticks, trackballs and cursor keys are not good in operability. More specifically, operability of these input devices is not good enough in that it is not easy to finely indicate a moving direction, a moving distance, and/or a moving speed of an object. It is also difficult for these types of devices to quickly direct long-distance movement. These difficulties can cause users not to be allowed to control movement of an object precisely in a manner intended by users in various situations.
Japanese Unexamined Patent Application Publication No. 2002-318661 discloses a pointing device with a new feature. In the pointing device disclosed in Japanese Unexamined Patent Application Publication No. 2002-318661, it is allowed to specify the ratio of the moving distance of an object such as a cursor to the moving distance of a user's finger so that it is possible to finely control the movement of the cursor. However, if the ratio is specified in such a manner, it becomes necessary to move the finger a greater distance, and thus it becomes necessary for the pointing device to have a greater operation area. Conversely, if the pointing device is configured to be capable of directing large-distance movement with a small operation area, the result is necessity of a plurality of scrolling operations and/or low operation sensitivity. Any way, such a configuration results in low operability.